Dentifrice composition

ABSTRACT

DENTIFRICE COMPOSITION CONTAINING A MONOFLUOROPHOSPHATE SALT AND AS A POLISHING MATERIAL AT LEAST A MAJOR AMOUNT OF FINE PARTICLE SIZE ALUMINA. PREFERABLY THE ALUMINA IS ALPHA ALUMINA TRIHYDRATE AND IS MIXED WITH INSOLUBLE ALKALI METAL METAPHOSPHATE, THE AMOUNT OF SAID ALUMINA BEING AT LEAST ABOUT EQUAL OF THE AMOUNT OF SAID ALKALI METAL METAPHOSPHATE. THIS DENTIFRICE RETAINS A DESIRABLE LEVEL OF SOLUBLE FLUORIDE UPON AGING.

United States Patent Int. Cl. A61k 7/16' US. Cl. 424-52 7 ClaimsABSTRACT OF THE DISCLOSURE Dentifrice composition containing amonofluorophosphate salt and as a polishing material at least a majoramount of fine particle size alumina. Preferably the alumina is alphaalumina trihydrate and is mixed with insoluble alkali metalmetaphosphate, the amount of said alumina being at least about equal ofthe amount of said alkali metal metaphosphate. This dentifrice retains adesirable level of soluble fluoride upon aging.

This application is a Continuation-In-Part of Ser. No. 126,350, filedMar. 19, 1971, now abandoned, which is a Continuation-In-Part of Ser.No. 818,098, filed Apr. 21, 1969, now abandoned.

The present invention relates to a dentifrice composition containing asa fluorine providing material a water soluble monofluorophosphate salt.

Various fluorine providing materials including water solublemonofluorophosphate salts have been used in dentifrice compositions. Thepolishing materials which may be used in such dentifrices vary,depending in part upon the particular fluorine providing materialemployed. Thus fluorine providing materials and polishing materials havebeen the subject of much investigation in order to find dentifricescontaining such fluorine providing materials and polishing materialswhich dentifrices retain a high proportion of soluble fluoride from thefluorine providing material upon storage and aging.

It is an object of this invention to provide a dentifrice composition inwhich the fluorine providing material is a monofluorophosphate salt,which dentifrice retains a desirable level of fluoride upon aging.

Other objects will be apparent from consideration of the followingdescription.

In accordance with certain of its aspects, this invention relates to adentifrice composition comprising a water soluble monofluorophosphatesalt in amount which provides about 0.01-1% fluorine to said compositionand about 20-95% by weight of polishing material comprising at least amajor amount of alumina in which at least about 85% of the particles areless than 20 microns in size and selected from the group consisting ofalpha alumina trihydrate, kappa type alumina, gamma phase alumina, betaphase alumina, microcrystalline alumina and mixtures thereof.

The water soluble monofluorophosphate salt used in the instantcomposition is preferably an alkali metal monofluorophosphate such assodium monofluorophosphate, lithium monofluorophosphate, potassiummonofluorophosphate and ammonium monofluorophosphate. The preferred saltis sodium monofluorophosphate, Na PO F, which, as commerciallyavailable, may vary considerably in purity. It may be used in anysuitable purity provided that any impurities do not substantiallyadversely affect the desired properties. In general, the purity isdesirably at least about 80%. For best results, it should be at least 85and preferably at least 90% by weight of sodium monofluorophosphate withthe balice ance being primarily impurities or by-products of manufacturesuch as sodium fluoride, water-soluble sodium phosphate salt, and thelike. Expressed in another way, the sodium monofluorophosphate employedshould have a total fluoride content of above 12%, preferably above12.7%; a content of not more than 1.5%, preferably not more than 1.2% offree sodium fluoride; and a sodium monofluorophosphate content of atleast 12%, preferably at least 12.1%, all calculated as fluorine.

Other monofluorophosphate salts which have sufficient Water solubilityfor use in the instant invention include calcium monofluorophosphate,magnesium monofluorophosphate and aluminum monofluorophosphate. Inaccordance with this invention the term monofluorophosphate alsoincludes monofluorophosphates such as N21 P O F, K4P3O9F, Na KP O F,

and Li4P309F.

Typically, the monofluorophosphate is present in amount which providesabout 0.01-1% fluorine to the dentifrice. Thus, sodiummonofluorophosphate is present, typically in amount of about 0.05% toabout 7.6%.

Alumina may be the sole polishing agent. Upon aging, the solublemonofluorop'hosphate as fluoride retained in the dentifrice can bemagnified if the alumina is mixed with another polishing agent such asan alkali metal metaphosphate, in a ratio of the other polishing agentto alumina of from about 1:500 to about 1:1.

The insoluble alkali metal metaphosphate which may be used in thepolishing material are preferably the insoluble sodium and potassiumsalts of polymetaphosphoric acid. These materials are known in the art.The insoluble sodium metaphosphate is preferred. Such materials may beformed in any suitable manner, as illustrated by Thorpes Dictionary ofApplied Chemistry, Vol.9 (4th ed.), pp. 510-511. The forms of insolublesodium metaphosphate known as Madrells salt and Kurrols salt are furtherexamples of suitable materials. These metaphosphate salts exhibit only aminute solubility in Water, and are commonly referred to as insolublemetaphosphates therefore. There is present a minor amount of solublephosphate material as impurities, usually of the order of a few percentsuch as up to about 4% by weight. The amount of soluble trimetaphosphatein the case of insoluble sodium metaphosphate may be reduced by washingwith water if desired. The insoluble alkali metal metaphosphate istypically employed in powder form of a size such that no more than about1% of the material is larger than about 37 microns.

The alumina employed in accordance with the instant invention is smallin particle size, i.e., at least about of the particles are smaller than20 microns and is preferably hydrated, such as that classified asgi'bbsite (alpha alumina trihydrate) and normally represented chemicallyas A1 O -3HgO or A1(OH) The average particle size of gibbsite isgenerally about 6 to 9 microns with the following size distribution:

Microns Percent 30 94-99 20 85-93 10 56-67 5 28-40 of gibbsite and isparticularly highly desirable. The average particle size of C333 aluminais about 2.5-8.5 microns. It is obtained by fine grinding of the gradeof alumina. trihydrate sold by Alcoa as C33.

When a minor polishing agent such as insoluble alkali metalmetaphosphate is employed, its ratio to alumina is from about 1:500 tosubstantially 1:1, that is about equal. Dentifrices containing thesepolishing components and water soluble monofluorophosphate salt retaindesirable levels of soluble fluoride, for example, at least about 40% ofthe original content of monofluorophosphate after accelerated aging ofthe dentifrice for nine weeks at about 49 C. Suitable ratios ofinsoluble alkali metal metaphosphate to alumina may vary fromsubstantially 1:1 to about 1:500, preferably to about 1:47.25. Typicallyhighly desirable ratios are in the range of about 1:3 to about 1:9. Whenthe ratio of the metaphosphate to the alumina is substantially 1:1, theweight amount of metaphosphate may be in slight excess, in view of thesmall amount of soluble content of the metaphosphate. In addition toalumina and insoluble alkali metal metaphosphate, or in place of theinsoluble alkali metal metaphosphate, the polishing material may alsocontain a minor amount, say about 0.5% to 5%, preferably about 1% of anadditional polishing component to aid in desirable polishing of dentalenamel. Typical examples of such components include water insolublealkaline earth metal phosphates, such as anhydrous dicalcium phosphate,dicalcium phos phate dihydrate, tricalcium phosphate, calcium carbonate/calcium, pyrophosphate, trimagnesium phosphate silica and the like.

The total polishing material content of the dentifrice is variable, butwill generally be up to about 95% by weight of the total composition. Inthe case of a dental cream, such polishing agents will generally beabout 20% to about 75%, and preferably about 40% to 55%, whereas intooth powders the polishing agents will usually be in greaterproportion, such as about 70% to about 95%.

In the preparation of tooth powders, it is usually suflicient to admixmechanically, for example, by milling, the various solid ingredients, inappropriate quantities and particle sizes.

Any suitable surface active or detersive material may be included in thedentifrice compositions. Such compatible materials are desirable toprovide additional detersive, foaming and antibacterial-propertiesdepending upon the specific type of surface active material and areselected similarly. These detergents are water-soluble compoundsusually, and may be anionic, nonionic or cationic in structure. It ispreferred to use the water-soluble nonsoap or synthetic organicdetergents usually. Suitable detersive materials are known and include,for example, the watersoluble salts of higher fatty acid monoglyceridemonosulfate detergent (e.g. sodium coconut fatty acid monoglyceridemonosulfate), higher alkyl sulfate (e.g. sodium lauryl sulfate), alkylaryl sulfonate (e.g. sodium dodecyl benzene sulfonate, higher fatty acidesters of 1,2- dihydroxy propane sulfonate (e.g. sodium coconut fattyacid ester of 1,2-dihydroxy propane sulfonate) and the like.

The various surface active materials may be used in any suitable amount,generally from about 0.05 to about by weight, and preferably from about0.5 to 5% by weight of the dentifrice composition.

It is a further embodiment of the present invention to use thesubstantially saturated higher aliphatic acyl amides of lower aliphaticamino carboxylic acid compounds, such as those having 12 to 16 carbonsin the acyl radical. The amino acid portion is derived generally fromthe lower aliphatic saturated monoaminocarboxylic acids having about 2to 6 carbons, usually the monocarboxylic acid compounds. Suitablecompounds are the fatty acid amides of glycine, sarcosine, alanine,3-aminopropanoic acid and valine having about 12 to 16 carbons in theacyl group.

It is preferred to use the N-lauroyl, myristoyl and palmitoyl sarcosidecompounds however for optimum effects.

The amide compounds may be employed in the form of the free acid orpreferably as the water-soluble salts thereof, such as the alkali metal,ammonium, amine and alkylolamine salts. Specific examples thereof aresodium and potassium N-lauroyl, myristoyl and palmitoyl sarcosides,ammonium and ethanolamine N-lauroyl sarcoside, N-lauroyl sarcosine, andsodium N-lauroyl glycide and alanine. For convenience herein, referenceto amino carboxylic acid compound, sarcoside, and the like refers tosuch compounds having a free carboxylic group or the water-solublecarboxylate salts.

Such materials are utilized in pure or substantially pure form. Theyshould be as free as practicable from soap or similar higher fatty acidmaterial which tends to reduce the activity of these compounds. In usualpractice, the amount of such higher fatty acid material is less than 15%by weight of the amide and insuflicient to substantially adverselyaffect it, and preferably less than about 10% of said amide material.

In dental cream formulations, the liquids and solids should beproportioned to form an extrudable creamy mass of desirable consistency.In general, liquids in the dental cream will comprise chiefly water,glycerine, sorbitol, propylene glycol, or the like, including suitablemixtures thereof. It is advantageous usually to use a mixture of bothwater and a humectant or binder such as glycerine or sorbitol. It ispreferred to use glycerine. The total liquid content will generally beabout 2075% by weight of the formulation. It is preferred to use also agelling agent in dental creams such as the natural and synthetic gum andgum-like material, e.g. Irish moss, gum tragacanth, sodiumcarboxymethylcellulose, polyvinylpyrrolidone, starch and the like. TheIrish moss and sodium carboxymethylcellulose are compatible particularlyand are preferred gelling agents as illustrated. The gum content isusually in an amount up to about 10% and preferably about 0.5-5% byweight of the formulation.

Various other materials may be incorporated in the oral preparations ofthis invention. Examples thereof are coloring or whitening agents,preservatives, silicones, chlorophyll compounds and ammoniated materialssuch as urea, diammoniumphosphate and mixtures thereof. These adjuvantsare incorporated in the instant compositions in amounts which do notsubstantially adversely affect the properties and characteristicssuitably selected and used in proper amount depending upon theparticular type of preparation involved.

For some purposes it may be desirable to include antibacterial agents inthe compositions of the present invention. Typical antibacterial agentswhich may be used in amounts of about 0.01% to about 5%, preferablyabout 0.05% to about 1.0%, by weight of the dentifrice compositioninclude:

N -4(chlorobenzyl)-N -(2,4-dichlorobenzyl)biguanide;

pchlorophenyl biguanide;

4-chlorobenzhydryl biguanide;

4-chlorobenzhydrylguanylurea;

N-3-lauroxypropyl-N -p-chlorobenzylbiguanide;

1,6-di-p-chlorophenylbiguanidehexane;

1- (lauryldimethylammonium) -8- (p-chlorobenzyldimethylammonium) octanedichloride;

5,6-dichloro-2-guanidinobenzimidazole;

N -p-chlorophenyl-N -laurylbiguanide;

5-amin0-1,3-bis(2-ethylhexyl)-5-methylhexahydropyrimidine;

and their non-toxic acid addition salts.

Any suitable flavoring or sweetening materials may be employed informulating a flavor for the compositions of the present invention.Examples of suitable flavoring constituents include the flavoring oils,e.g., oils of Spearmint, peppermint, Wintergreen, sassafras, clove,sage, eucalyptus, marjoram, cinnamon, lemon and orange, as well asmethylsalicylate. Suitable sweetening agents include sucrose, lactose,maltose, sorbitol, sodium cyclamate and saccharine. Suitably, flavor andsweetening agent may together comprise from about 0.01 to 5% or more ofthe instant invention.

The dental creams should have a pH practicable for use. A pH range of 6to 9 is particularly desirable. The reference to the pH is meant to bethe pH determination directly on the dental cream. If desired, materialssuch as citric acid may be added to adjust the pH to say 6.5 to 7.5.When citric acid is present, the dental cream typically retains at leastabout 40% of the original content of monoflnorophosphate afteraccelerated aging for nine weeks at about 49 C. When the pH is notadjusted with materials such as citric acid, the dental cream typicallyretains at least about 45% and generally more than 50% of the originalcontent of monofluorophosphate after accelerated aging for nine weeks atabout 49 C.

The instant dentifrice preparations are highly eflicacious in use. Whenprepared as dental creams they exhibit desirable cosmetic andrheological properties and may be stored and dispensed from conventionalcollapsible tubes. For example, compositions of the invention may bestored in unlined aluminum tubes.

The following specific examples are further illustrative of the natureof the present invention, but it is to be understood that the inventionis not limited thereto. The compositions are prepared in the usualmanner and all amounts of the various ingredients are by weight unlessotherwise specified.

Example 1 The following dentifrices are prepared. The content of sodiummonofluorophosphate in each is equivalent to 0.1% fluoride ion:

Percent A B C Humectant (glycerine) 18. 18. 0 18. 0 Sodium b 0. 0. 5 0.5 Sodium saccharine 0. 2 0. 2 0.2 Citric acid 0. 1 0.2 Sodiummonofiuorophosphate 0. 76 0. 76 0. 76 Insoluble sodium metaphosphate 5.05. 0 Hydrated alumina 333) 42. 25 42. 25 52. O Anhydrousdicalciumphosphate 1. 0 1. 0 Sodium carboxymethyleellulose 1. 2 1. 2 1.2 Sodium N -lau1oyl sarcosinate 2. 0 2.0 2. 0 Flavor 0. 9 0. 9 0. 9Water Q.S. Q.S. Q.S

Percent soluble monofiuorophosphate as fluoride at 49 C. for-Composition 3 weeks 6 weeks 9 weeks Thus, all dentifrices retain solublemonofluorophosphate as fluoride and the presence of some insolublemetaphosphate markedly increases the ability of Compositions A and B toretain soluble monofluorophosphate as fluoride.

Example 2 Dentifrices corresponding to Dentifrice A of Example 1 inwhich the polishing material is varied as indicated below are preparedand aged at 49 C. for several weeks. The soluble fluoride content of thedentifrice is also indicated.

Modified dentifrice A of Example 1 A A: A

Polishing material percent:

Insoluble sodium metaphosphate 1. 0 3.0 12.0

Hydrated alumina (C333) 46. 25 44. 25 35. 25

Anhydrous dicalcium phosphate 1. 0 1.0 1. 0

Percent soluble monofiuorophosphate as fluoride at 49 C. for-Composition 3 weeks 6 weeks 9 weeks Each of these dentifrices retains ahigh level of soluble monofluorophosphate as fluoride.

Example 3 Dentifrice corresponding to dentifrice B of Example 1 in whichthe polishing material is varied as indicated below is prepared and agedat 49 C. for several weeks. The soluble fluoride content of thedentifrice is also indicated.

Modified dentifrice B of Example l B Polishing material, percent:

Insoluble sodium metaphosphate.-. 1. 0 Hydrated alumina (C333) 6. 25Anhydrous dicalclum phosphate..- 1.0

Percent soluble monofiucropliosphate as fluoride at 49 O. for-Composition 3 weeks 6 weeks 9 weeks This dentifrice too retains a highlevel of more than 40% of soluble monofluorophosphate as fluoride evenafter accelerated aging at 49 C. for 9 weeks.

Example 4 Modified dentifrice A of Example A4 A5 A6 A1 A; A

Humectant, percent:

Glycerine 6. 0 20.0 22. 0 15.0 6. 0 6. 0 Sorbitol (70%) 16. 0 16.0 16. 0Polishing material, percent:

Insoluble sodium metaphosphate 5. 0 5. 0 5.0 5. 0 12. 0 24. 0 Hydratedalumina (C333) 42. 25 42. 25 42. 25 35. 25 23. 25 Anhydrous dicalciumphosphate 1.0 1. 0 l. 0 1. O 1. 0 1. 0

Percent soluble monofiuorophosphate as fluoride at 40 C. for--Composition 3 weeks 6 weeks 9 weeks Each of these dentifrices retains ahigh level of soluble monofluorophosphate as fluoride. In dentifrice Athe amount of the alumina is substantially equal to the amount of theinsoluble portion of the metaphosphate.

Example 5 Dentifrices corresponding to dentifrice A of Example 1 inwhich Irish moss replaces sodium carboxymethyl cellulose and in whichthe humectant and polishing material are varied as indicated below areprepared and aged at 49 C. for several Weeks. The soluble fluoridecontent of each dentifrice is also indicated below.

Irish Moss modified dentifrice A of Example 1 Humectant, percent:

Glycerino Sorbitol (70%) Polishing material, percent:

Insoluble sodium metaphosphato Hydrated alumina (C333) Percent solublemonoiluorophosphate as fluoride at 49 C. for

Composition 3 weeks 6 weeks 9 W"OkS A 0. 082 0. 073 O. 057 A 0. 084 0.075 0. 068

Each of these dentifrices retains a high level of solublemonofluorophosphate as fluoride. In dentifrice A the amount of thealumina is substantially equal to the amount of the insoluble portion ofthe metaphosphate.

Example 6 Dentifrice corresponding to dentifrice B of Example 1 in whichthe humectant and polishing material are varied as indicated below areprepared and aged at 49 C. for several weeks. The soluble fluoridecontent of each dentifrice is also indicated below.

Modified dentifrice B of Example 1 B2 B3 Humectant, percent:

Glycen'ne 6.0 22. Sorbitol 70%) 16. 0

Polishing material, percent:

Insoluble sodium metaphosphate 5. 0 5. 0 Hydrated alumina (C333)Anhydrous dicalcium phosphate Percent soluble monoiiuorophosphate asfluoride at 49 C. for- Composition 3 weeks 6 weeks 9 weeks Each of thesedentifrices too retains a high level of at least about 40% of solublemonofiuorophosphate as fluoride even after accelerated aging at 49 C.for 9 weeks.

Example 7 Modified dentifrice B of Example 1 B4 B5 B6 Polishingmaterial, percent:

Insoluble sodium metaphosphate.. 1. 0 0.5 0. 1 Hydrated alumina (C333)47. 25 47. 75 48.15

Percent soluble monofiuorophosphate as fluoride at 49 C. for

Composition 3 weeks 6 weeks 9 weeks Each of these dentifrices too retainsatisfactorily high levels of soluble monofluorophosphate as fluorideeven after accelerated aging at 49 C. for 6 to 9 weeks.

It will be apparent to one skilled in the art that various modificationsof the above examples may be made thereto.

We claim:

1. A dentifrice composition comprising a water solublemonofluorophosphate salt in amount which provides about 0.01-1% fluorineto said composition and about 2095% by weight of a water insolublecompatible polishing material comprising at least a major amount ofalumina in which at least about of the particles are less than 20microns in size and selected from the group consisting of alpha aluminatrihydrate, kappa type alumina, gamma phase alumina, beta phase alumina,microcrystalline alumina and mixtures thereof and an insoluble alkalimetal metaphosphate, the ratio of said metaphosphate to said aluminabeing from about 1:500 to about 1:1.

2. The dentifrice composition of Claim 1 wherein said alumina is alphaalumina trihydrate having an average particle size of about 2.5-8.5microns.

3. The dentifrice claimed in Claim 1 wherein said alumina is alphaalumina trihydrate having an average particle size of about 2.5-8.5microns.

4. The dentifrice composition of Claim 1 wherein said metaphosphate isinsoluble sodium metaphosphate and the ratio of said metaphosphate tosaid alumina is from about 1:47.25 to about 1:1.

5. The dentifrice composition of Claim 1 wherein said metaphosphate isinsoluble sodium metaphosphate and the ratio of said metaphosphate tosaid alumina is from about 1:9 to about 1:3.

6. The dentifrice composition of Claim 1 wherein said polishing materialalso contains a minor amount of a water insoluble alkaline earth metalphosphate.

7. The dentifrice composition of Claim 6 wherein said water insolublealkaline earth metal phosphate is anhydrous dicalcium phosphate.

References Cited UNITED STATES PATENTS 3,034,967 5/1962 Apperson et al.424-52 2,818,371 12/1957 Wessinger 424-52 FOREIGN PATENTS 1,076,8517/1967 Great Britain 424-52 1,559,196 1/1969 France 42449 OTHERREFERENCES Ericsson, Acta Odontal. Scand., Vol. 20, pp. 44145l,

RICHARD L. HUFF, Primary Examiner US. Cl. X.R.

